1. Field of the Invention
The present invention relates to a manufacturing method for a heating resistor element component (thermal head) which is used in a thermal printer typically mounted onto a compact information equipment terminal such as a compact handy terminal, and performs printing on a thermal recording medium through selective driving of a plurality of heating elements based on print data.
2. Description of the Related Art
Recently, thermal printers have been widely used in compact information equipment terminals. The compact information equipment terminals are driven by a battery, which leads to strong demands for electric power saving of the thermal printers. Accordingly, there have been growing demands for thermal heads having high heating efficiency.
As to increasing efficiency of the thermal head, there is known a method of forming a heat insulating layer in a lower layer of a heating resistor (for example, see Patent Document JP 2007-83532 A). Among an amount of heat generated in the heating resistor, an amount of upper-transferred heat which is transferred to a wear-resistant layer formed above the heating resistor becomes larger than an amount of lower-transferred heat which is transferred to an insulating substrate located under the heating resistor, and thus energy efficiency required during the printing can be sufficiently obtained.
In the case where the thermal head as described above is manufactured, one undercoat is placed on one substrate. Accordingly, a size (in particular, length and width) of the under coat is increased, and the thus manufactured thermal head is difficult to be handled, leading to a fear that the undercoat may be damaged during transportation.
In addition, a bonding area between the substrate and the undercoat is increased, which leads to a fear that a spot having an adhesion failure is generated between the undercoat and the substrate, the undercoat peels off from the substrate during manufacturing process, and a yield is reduced.